Fabrics and other fibrous substrates are often treated chemically to provide particular surface properties such as repellency, stain resistance soil resistance and the like. Various modifying additives or finishing agents such as softeners, stiffeners, lubricants, and other known additives are also commonly employed to provide a suitable commercial substrate, such as a textile or carpet having the desired surface properties. These modifications typically increase the oleophilicity of the substrate, thereby significantly increasing its tendency to accept oily stains and reducing its ability to release such stains during laundering. While stain resistance helps to inhibit the initial staining of a substrate, once stained, it is important that the substrate have good stain release properties for removal of the stain. Thus, reduction of the stain release properties is undesirable.
Therefore such substrates need to be co-treated with hydrophilic materials to help reduce their oleophilicity and facilitate stain release during laundering. Examples of such materials, which are referred to as stain or soil release agents, include carboxymethylcellulose, polyacrylic acid, or fluorochemical-based systems. U.S. Pat. No. 5,509,939 discloses a process for imparting oil-, water- and stain-repellency and soil-release properties to a substrate which comprises applying to the substrate urea linkage-containing alkoxypolyoxyalkylene fluorocarbamates prepared by reacting (a) at least one polyisocyanate which contains at least three isocyanate groups with (b) at least one fluorochemical reagent which contains one functional group which has at least one H and at least two C atoms each of which contains at least two F atoms, (c) at least one hydrophilic, water-solvatable reagent which contains a single functional group which has at least one reactive H, (d) at least one reagent which contains one reactive H and which on reaction with an isocyanate group yields functionality which has abeyant chemical reactivity with fibrous substrates and (e) then with water, reactants (b), (c) and (d) being reacted with 55% to 95% of said isocyanate groups, and water with the remainder. Preferably said fluorochemical reagent is a perfluoroalkylethyl alcohol mixture of the formula F(CF2)aCH2CH2OH, wherein a is selected from a predominantly 6, 8 and 10 mixture or from a predominantly 8, 10 and 12 mixture.
In recent years demand has increased for more hydrophilic stain release properties than previously provided. It is advantageous to have greater hydrophilicity as it results in easier cleaning of the treated substrate due to enhanced wetability. Higher hydrophilicity also provides better overall moisture management via wicking, which is desirable for textiles used in protective and athletic garments. This demand has typically been met by reformulating the known treatment compositions so as to use greater amounts of surfactants or wetting agents. However, this change in formulation has been found to cause soil pickup, or redeposition of soil onto the textile, during home laundry washing. Thus there is a need for a stain release agent that provides greater hydrophilicity without the need for adding large amounts of surfactants or wetting agents to the composition. The present invention provides such an agent to provide hydrophilicity and stain release to treated substrates.